mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-24 07:06:39 +00:00
136 lines
3.1 KiB
C++
136 lines
3.1 KiB
C++
/*
|
|
* Copyright (c)2019 ZeroTier, Inc.
|
|
*
|
|
* Use of this software is governed by the Business Source License included
|
|
* in the LICENSE.TXT file in the project's root directory.
|
|
*
|
|
* Change Date: 2023-01-01
|
|
*
|
|
* On the date above, in accordance with the Business Source License, use
|
|
* of this software will be governed by version 2.0 of the Apache License.
|
|
*/
|
|
/****/
|
|
|
|
#ifndef ZT_SHAREDPTR_HPP
|
|
#define ZT_SHAREDPTR_HPP
|
|
|
|
#include "Mutex.hpp"
|
|
#include "AtomicCounter.hpp"
|
|
|
|
namespace ZeroTier {
|
|
|
|
/**
|
|
* Simple zero-overhead introspective reference counted pointer
|
|
*
|
|
* This is an introspective shared pointer. Classes that need to be reference
|
|
* counted must list this as a 'friend' and must have a private instance of
|
|
* AtomicCounter called __refCount.
|
|
*/
|
|
template<typename T>
|
|
class SharedPtr
|
|
{
|
|
public:
|
|
ZT_ALWAYS_INLINE SharedPtr() : _ptr((T *)0) {}
|
|
ZT_ALWAYS_INLINE SharedPtr(T *obj) : _ptr(obj) { ++obj->__refCount; }
|
|
ZT_ALWAYS_INLINE SharedPtr(const SharedPtr &sp) : _ptr(sp._getAndInc()) {}
|
|
|
|
ZT_ALWAYS_INLINE ~SharedPtr()
|
|
{
|
|
if (_ptr) {
|
|
if (--_ptr->__refCount <= 0)
|
|
delete _ptr;
|
|
}
|
|
}
|
|
|
|
ZT_ALWAYS_INLINE SharedPtr &operator=(const SharedPtr &sp)
|
|
{
|
|
if (_ptr != sp._ptr) {
|
|
T *p = sp._getAndInc();
|
|
if (_ptr) {
|
|
if (--_ptr->__refCount <= 0)
|
|
delete _ptr;
|
|
}
|
|
_ptr = p;
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
/**
|
|
* Set to a naked pointer and increment its reference count
|
|
*
|
|
* This assumes this SharedPtr is NULL and that ptr is not a 'zombie.' No
|
|
* checks are performed.
|
|
*
|
|
* @param ptr Naked pointer to assign
|
|
*/
|
|
ZT_ALWAYS_INLINE void set(T *ptr)
|
|
{
|
|
zero();
|
|
++ptr->__refCount;
|
|
_ptr = ptr;
|
|
}
|
|
|
|
/**
|
|
* Swap with another pointer 'for free' without ref count overhead
|
|
*
|
|
* @param with Pointer to swap with
|
|
*/
|
|
ZT_ALWAYS_INLINE void swap(SharedPtr &with)
|
|
{
|
|
T *tmp = _ptr;
|
|
_ptr = with._ptr;
|
|
with._ptr = tmp;
|
|
}
|
|
|
|
ZT_ALWAYS_INLINE operator bool() const { return (_ptr != (T *)0); }
|
|
ZT_ALWAYS_INLINE T &operator*() const { return *_ptr; }
|
|
ZT_ALWAYS_INLINE T *operator->() const { return _ptr; }
|
|
|
|
/**
|
|
* @return Raw pointer to held object
|
|
*/
|
|
ZT_ALWAYS_INLINE T *ptr() const { return _ptr; }
|
|
|
|
/**
|
|
* Set this pointer to NULL
|
|
*/
|
|
ZT_ALWAYS_INLINE void zero()
|
|
{
|
|
if (_ptr) {
|
|
if (--_ptr->__refCount <= 0)
|
|
delete _ptr;
|
|
_ptr = (T *)0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @return Number of references according to this object's ref count or 0 if NULL
|
|
*/
|
|
ZT_ALWAYS_INLINE int references()
|
|
{
|
|
if (_ptr)
|
|
return _ptr->__refCount.load();
|
|
return 0;
|
|
}
|
|
|
|
ZT_ALWAYS_INLINE bool operator==(const SharedPtr &sp) const { return (_ptr == sp._ptr); }
|
|
ZT_ALWAYS_INLINE bool operator!=(const SharedPtr &sp) const { return (_ptr != sp._ptr); }
|
|
ZT_ALWAYS_INLINE bool operator>(const SharedPtr &sp) const { return (_ptr > sp._ptr); }
|
|
ZT_ALWAYS_INLINE bool operator<(const SharedPtr &sp) const { return (_ptr < sp._ptr); }
|
|
ZT_ALWAYS_INLINE bool operator>=(const SharedPtr &sp) const { return (_ptr >= sp._ptr); }
|
|
ZT_ALWAYS_INLINE bool operator<=(const SharedPtr &sp) const { return (_ptr <= sp._ptr); }
|
|
|
|
private:
|
|
ZT_ALWAYS_INLINE T *_getAndInc() const
|
|
{
|
|
if (_ptr)
|
|
++_ptr->__refCount;
|
|
return _ptr;
|
|
}
|
|
T *_ptr;
|
|
};
|
|
|
|
} // namespace ZeroTier
|
|
|
|
#endif
|